U.S. patent application number 12/957561 was filed with the patent office on 2011-09-15 for bipolar plate for fuel cell, method of manufacturing the bipolar plate, and fuel cell including the bipolar plate.
This patent application is currently assigned to Samsung Electronics Co., Ltd.. Invention is credited to Kyoung-hwan Choi, Ji-rae KIM, Tae-won Song, Jung-seok Yi.
Application Number | 20110223522 12/957561 |
Document ID | / |
Family ID | 44560320 |
Filed Date | 2011-09-15 |
United States Patent
Application |
20110223522 |
Kind Code |
A1 |
KIM; Ji-rae ; et
al. |
September 15, 2011 |
BIPOLAR PLATE FOR FUEL CELL, METHOD OF MANUFACTURING THE BIPOLAR
PLATE, AND FUEL CELL INCLUDING THE BIPOLAR PLATE
Abstract
A bipolar plate for a fuel cell includes a metal plate and a
coating layer disposed on a surface of the metal plate. The coating
layer includes a polymer of an oxazine-based compound,
particularly, a benzoxazine-based compound and a conducting
material. A method of manufacturing the bipolar plate includes
coating a surface of a metal plate with a coating layer forming
composition including at least one oxazine-based compound, a
conducting material, and a solvent; and thermally treating the
metal plate coated with the coating layer forming composition. A
fuel cell includes the bipolar plate.
Inventors: |
KIM; Ji-rae; (Seoul, KR)
; Yi; Jung-seok; (Seoul, KR) ; Song; Tae-won;
(Yongin-si, KR) ; Choi; Kyoung-hwan; (Suwon-si,
KR) |
Assignee: |
Samsung Electronics Co.,
Ltd.
Suwon-si
KR
|
Family ID: |
44560320 |
Appl. No.: |
12/957561 |
Filed: |
December 1, 2010 |
Current U.S.
Class: |
429/518 ;
427/115 |
Current CPC
Class: |
H01M 8/0228 20130101;
Y02E 60/50 20130101; Y02P 70/50 20151101; H01M 8/0221 20130101;
H01M 8/0206 20130101 |
Class at
Publication: |
429/518 ;
427/115 |
International
Class: |
H01M 4/60 20060101
H01M004/60; H01M 4/04 20060101 H01M004/04; H01M 8/00 20060101
H01M008/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 12, 2010 |
KR |
10-2010-0022426 |
Claims
1. A bipolar plate for a fuel cell, comprising: a metal plate; and
a coating layer disposed on a surface of the metal plate, the
coating layer including a polymer of an oxazine-based compound and
a conducting material, wherein the oxazine-based compound comprises
at least one compound selected from among the compounds represented
by Formulae 1, 2, 3, 4, 5, 5A and 6 below: ##STR00061## wherein, in
Formula 1, R.sub.1 through R.sub.4 are each independently a
hydrogen atom, a substituted or unsubstituted C.sub.1-C.sub.20
alkyl group, a substituted or unsubstituted C.sub.1-C.sub.20 alkoxy
group, a substituted or unsubstituted C.sub.2-C.sub.20 alkenyl
group, a substituted or unsubstituted C.sub.2-C.sub.20 alkynyl
group, a substituted or unsubstituted C.sub.6-C.sub.20 aryl group,
a substituted or unsubstituted C.sub.6-C.sub.20 aryloxy group, a
substituted or unsubstituted C.sub.2-C.sub.20 heteroaryl group, a
substituted or unsubstituted C.sub.2-C.sub.20 heteroaryloxy group,
a substituted or unsubstituted C.sub.4-C.sub.20 carbon ring group,
a substituted or unsubstituted C.sub.4-C.sub.20-carbocyclic alkyl
group, a substituted or unsubstituted C.sub.2-C.sub.20 heterocyclic
group, a halogen atom, a hydroxyl group, or a cyano group; and
R.sub.5 is a substituted or unsubstituted C.sub.1-C.sub.20 alkyl
group, a substituted or unsubstituted C.sub.1-C.sub.20 alkoxy
group, a substituted or unsubstituted C.sub.2-C.sub.20 alkenyl
group, a substituted or unsubstituted C.sub.2-C.sub.20 alkynyl
group, a substituted or unsubstituted C.sub.6-C.sub.20 aryl group,
a substituted or unsubstituted C.sub.6-C.sub.20 aryloxy group, a
substituted or unsubstituted C.sub.7-C.sub.20 arylalkyl group, a
substituted or unsubstituted C.sub.2-C.sub.20 heteroaryl group, a
substituted or unsubstituted C.sub.2-C.sub.20 heteroaryloxy group,
a substituted or unsubstituted C.sub.2-C.sub.20 heteroarylalkyl
group, a substituted or unsubstituted C.sub.4-C.sub.20 carbocyclic
group, a substituted or unsubstituted C.sub.4-C.sub.20 carbocyclic
alkyl group, a substituted or unsubstituted C.sub.2-C.sub.20
heterocyclic group, or a substituted or unsubstituted
C.sub.2-C.sub.20 heterocyclic alkyl group, ##STR00062## in Formula
2, R.sub.5' is a substituted or unsubstituted C.sub.1-C.sub.20
alkyl group, a substituted or unsubstituted C.sub.1-C.sub.20 alkoxy
group, a substituted or unsubstituted C.sub.2-C.sub.20 alkenyl
group, a substituted or unsubstituted C.sub.2-C.sub.20 alkynyl
group, a substituted or unsubstituted C.sub.6-C.sub.20 aryl group,
a substituted or unsubstituted C.sub.6-C.sub.20 aryloxy group, a
substituted or unsubstituted C.sub.7-C.sub.20 arylalkyl group, a
substituted or unsubstituted C.sub.2-C.sub.20 heteroaryl group, a
substituted or unsubstituted C.sub.2-C.sub.20 heteroaryloxy group,
a substituted or unsubstituted C.sub.2-C.sub.20 heteroarylalkyl
group, a substituted or unsubstituted C.sub.4-C.sub.20 carbocyclic
group, a substituted or unsubstituted C.sub.4-C.sub.20 carbocyclic
alkyl group, a substituted or unsubstituted C.sub.2-C.sub.20
heterocyclic group, or a substituted or unsubstituted
C.sub.2-C.sub.20 heterocyclic alkyl group; and R.sub.6 is selected
from the group consisting of a substituted or unsubstituted
C.sub.1-C.sub.20 alkylene group, a substituted or unsubstituted
C.sub.2-C.sub.20 alkenylene group, a substituted or unsubstituted
C.sub.2-C.sub.20 alkynylene group, a substituted or unsubstituted
C.sub.6-C.sub.20 arylene group, a substituted or unsubstituted
C.sub.2-C.sub.20 heteroarylene group, --C(.dbd.O)--, and
--SO.sub.2--, ##STR00063## in Formula 3, A, B, C, D and E are all
carbon; or one or two of A, B, C, D and E is nitrogen and the
others are carbon; and R.sub.1 and R.sub.2 are linked to form a
ring, wherein the ring is a C.sub.6-C.sub.10 carbon ring group, a
C.sub.3-C.sub.10 heteroaryl group, a fused C.sub.3-C.sub.10
heteroaryl group, a C.sub.3-C.sub.10 heterocyclic group or a fused
C.sub.3-C.sub.10 heterocyclic group, ##STR00064## in Formula 4, A
is a substituted or unsubstituted C.sub.1-C.sub.20 heterocyclic
group, a substituted or unsubstituted C.sub.4-C.sub.20 cycloalkyl
group, or a substituted or unsubstituted C.sub.1-C.sub.20 alkyl
group; and R.sub.1 through R.sub.8 are each independently a
hydrogen atom, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20
alkoxy group, a C.sub.6-C.sub.20 aryl group, a C.sub.6-C.sub.20
aryloxy group, a C.sub.1-C.sub.20 heteroaryl group, a
C.sub.1-C.sub.20 heteroaryloxy group, a C.sub.4-C.sub.20 cycloalkyl
group, a C.sub.1-C.sub.20 heterocyclic group, a halogen atom, a
cyano group, or a hydroxyl group, wherein at least one of A and
R.sub.1 through R.sub.8 comprises a benzoxazine group, ##STR00065##
in Formula 5, R.sub.1 and R.sub.2 are each independently a
C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, a
C.sub.6-C.sub.20 aryl group, a C.sub.6-C.sub.20 aryloxy group or a
group represented by Formula 5A below, ##STR00066## in Formulae 5
and 5A, R.sub.3 is a hydrogen atom, a C.sub.1-C.sub.20 alkyl group,
a C.sub.1-C.sub.20 alkoxy group, a C.sub.6-C.sub.20 aryl group, a
C.sub.6-C.sub.20 aryloxy group, a halogenated C.sub.6-C.sub.20 aryl
group, a halogenated C.sub.6-C.sub.20 aryloxy group, a
C.sub.1-C.sub.20 heteroaryl group, a C.sub.1-C.sub.20 heteroaryloxy
group, a halogenated C.sub.1-C.sub.20 heteroaryl group, a
halogenated C.sub.1-C.sub.20 heteroaryloxy group, a
C.sub.4-C.sub.20 carbon ring group, a halogenated C.sub.4-C.sub.20
carbon ring group, a C.sub.1-C.sub.20 heterocyclic group or a
halogenated C.sub.1-C.sub.20 heterocyclic group. ##STR00067## in
Formula 6, at least two adjacent groups selected from among
R.sub.2, R.sub.3 and R.sub.4 are linked to form a group represented
by Formula 2A below, and the non-selected, remaining group is a
hydrogen atom, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20
alkoxy group, a C.sub.6-C.sub.20 aryl group, a C.sub.6-C.sub.20
aryloxy group, a halogenated C.sub.6-C.sub.20 aryl group, a
halogenated C.sub.6-C.sub.20 aryloxy group, a C.sub.1-C.sub.20
heteroaryl group, a C.sub.1-C.sub.20 heteroaryloxy group, a
halogenated C.sub.1-C.sub.20 heteroaryl group, a halogenated
C.sub.1-C.sub.20 heteroaryloxy group, a C.sub.4-C.sub.20 carbon
ring group, a halogenated C.sub.4-C.sub.20 carbon ring group, a
C.sub.1-C.sub.20 heterocyclic group or a halogenated
C.sub.1-C.sub.20 heterocyclic group; and at least two adjacent
groups selected from among R.sub.5, R.sub.6 and R.sub.7 are linked
to form the group represented by Formula 2A below, and the
non-selected, remaining group is a C.sub.1-C.sub.20 alkyl group, a
C.sub.1-C.sub.20 alkoxy group, a C.sub.6-C.sub.20 aryl group, a
C.sub.6-C.sub.20 aryloxy group, a halogenated C.sub.6-C.sub.20 aryl
group, a halogenated C.sub.6-C.sub.20 aryloxy group, a
C.sub.1-C.sub.20 heteroaryl group, a C.sub.1-C.sub.20 heteroaryloxy
group, a halogenated C.sub.1-C.sub.20 heteroaryl group, a
halogenated C.sub.1-C.sub.20 heteroaryloxy group, a
C.sub.4-C.sub.20 carbon ring group, a halogenated C.sub.4-C.sub.20
carbon ring group, a C.sub.1-C.sub.20 heterocyclic group or a
halogenated C.sub.1-C.sub.20 heterocyclic group, ##STR00068## in
Formula 2A, R.sub.1 is a substituted or unsubstituted
C.sub.1-C.sub.20 alkyl group, a substituted or unsubstituted
C.sub.1-C.sub.20 alkoxy group, a substituted or unsubstituted
C.sub.2-C.sub.20 alkenyl group, a substituted or unsubstituted
C.sub.2-C.sub.20 alkynyl group, a substituted or unsubstituted
C.sub.6-C.sub.20 aryl group, a substituted or unsubstituted
C.sub.6-C.sub.20 aryloxy group, a substituted or unsubstituted
C.sub.7-C.sub.20 arylalkyl group, a substituted or unsubstituted
C.sub.2-C.sub.20 heteroaryl group, a substituted or unsubstituted
C.sub.2-C.sub.20 heteroaryloxy group, a substituted or
unsubstituted C.sub.2-C.sub.20 heteroarylalkyl group, a substituted
or unsubstituted C.sub.4-C.sub.20 carbocyclic group, a substituted
or unsubstituted C.sub.4-C.sub.20 carbocyclic alkyl group, a
substituted or unsubstituted C.sub.2-C.sub.20 heterocyclic group,
or a substituted or unsubstituted C.sub.2-C.sub.20 heterocyclic
alkyl group; and * denotes the sites at which the at least two
adjacent groups selected from among R.sub.2, R.sub.3 and R.sub.4 of
Formula 6 and the at least two adjacent groups selected from among
R.sub.5, R.sub.6 and R.sub.7 of Formula 6 are linked,
respectively.
2. The bipolar plate of claim 1, wherein the conducting material
comprises at least one material selected from the group consisting
of carbon black, graphite and carbon nanotubes.
3. The bipolar plate of claim 1, wherein the amount of the
conducting material is in the range of about 0.25 parts to about 10
parts by weight based on 1 part by weight of the polymer of the
oxazine-based compound.
4. The bipolar plate of claim 1, wherein the metal plate comprises
a stainless steel plate, an aluminum plate or a carbon steel
plate.
5. The bipolar plate of claim 1, wherein the oxazine-based compound
comprises at least one compound selected from the compounds
represented by Formulae 7 through 14 below: ##STR00069##
##STR00070##
6. The bipolar plate of claim 1, wherein the surface of the metal
plate includes a groove.
7. A method of manufacturing a bipolar plate for a fuel cell, the
method comprising: coating a surface of a metal plate with a
coating layer forming composition comprising at least one
oxazine-based compound selected from among compounds represented by
Formulae 1, 2, 3, 4, 5, 5A and 6 below, a conducting material, and
a solvent; and thermally treating the metal plate coated with the
coating layer forming composition. ##STR00071## wherein in Formula
1, R.sub.1 through R.sub.4 are each independently a hydrogen atom,
a substituted or unsubstituted C.sub.1-C.sub.20 alkyl group, a
substituted or unsubstituted C.sub.1-C.sub.20 alkoxy group, a
substituted or unsubstituted C.sub.2-C.sub.20 alkenyl group, a
substituted or unsubstituted C.sub.2-C.sub.20 alkynyl group, a
substituted or unsubstituted C.sub.6-C.sub.20 aryl group, a
substituted or unsubstituted C.sub.6-C.sub.20 aryloxy group, a
substituted or unsubstituted C.sub.2-C.sub.20 heteroaryl group, a
substituted or unsubstituted C.sub.2-C.sub.20 heteroaryloxy group,
a substituted or unsubstituted C.sub.4-C.sub.20 carbon ring group,
a substituted or unsubstituted C.sub.4-C.sub.20 carbocyclic alkyl
group, a substituted or unsubstituted C.sub.2-C.sub.20 heterocyclic
group, a halogen atom, a hydroxyl group, or a cyano group; and
R.sub.5 is a substituted or unsubstituted C.sub.1-C.sub.20 alkyl
group, a substituted or unsubstituted C.sub.1-C.sub.20 alkoxy
group, a substituted or unsubstituted C.sub.2-C.sub.20 alkenyl
group, a substituted or unsubstituted C.sub.2-C.sub.20 alkynyl
group, a substituted or unsubstituted C.sub.6-C.sub.20 aryl group,
a substituted or unsubstituted C.sub.6-C.sub.20 aryloxy group, a
substituted or unsubstituted C.sub.7-C.sub.20 arylalkyl group, a
substituted or unsubstituted C.sub.2-C.sub.20 heteroaryl group, a
substituted or unsubstituted C.sub.2-C.sub.20 heteroaryloxy group,
a substituted or unsubstituted C.sub.2-C.sub.20 heteroarylalkyl
group, a substituted or unsubstituted C.sub.4-C.sub.20 carbocyclic
group, a substituted or unsubstituted C.sub.4-C.sub.20 carbocyclic
alkyl group, a substituted or unsubstituted C.sub.2-C.sub.20
heterocyclic group, or a substituted or unsubstituted
C.sub.2-C.sub.20 heterocyclic alkyl group, ##STR00072## in Formula
2, R.sub.5' is a substituted or unsubstituted C.sub.1-C.sub.20
alkyl group, a substituted or unsubstituted C.sub.1-C.sub.20 alkoxy
group, a substituted or unsubstituted C.sub.2-C.sub.20 alkenyl
group, a substituted or unsubstituted C.sub.2-C.sub.20 alkynyl
group, a substituted or unsubstituted C.sub.6-C.sub.20 aryl group,
a substituted or unsubstituted C.sub.6-C.sub.20 aryloxy group, a
substituted or unsubstituted C.sub.7-C.sub.20 arylalkyl group, a
substituted or unsubstituted C.sub.2-C.sub.20 heteroaryl group, a
substituted or unsubstituted C.sub.2-C.sub.20 heteroaryloxy group,
a substituted or unsubstituted C.sub.2-C.sub.20 heteroarylalkyl
group, a substituted or unsubstituted C.sub.4-C.sub.20 carbocyclic
group, a substituted or unsubstituted C.sub.4-C.sub.20 carbocyclic
alkyl group, a substituted or unsubstituted C.sub.2-C.sub.20
heterocyclic group, or a substituted or unsubstituted
C.sub.2-C.sub.20 heterocyclic alkyl group; and R.sub.6 is selected
from the group consisting of a substituted or unsubstituted
C.sub.1-C.sub.20 alkylene group, a substituted or unsubstituted
C.sub.2-C.sub.20 alkenylene group, a substituted or unsubstituted
C.sub.2-C.sub.20 alkynylene group, a substituted or unsubstituted
C.sub.6-C.sub.20 arylene group, a substituted or unsubstituted
C.sub.2-C.sub.20 heteroarylene group, --C(.dbd.O)--, and
--SO.sub.2--, ##STR00073## in Formula 3, A, B, C, D and E are all
carbon; or one or two of A, B, C, D and E is nitrogen and the
others are carbon; and R.sub.1 and R.sub.2 are linked to form a
ring, wherein the ring is a C.sub.6-C.sub.10 cycloalkyl group, a
C.sub.3-C.sub.10 heteroaryl group, a fused C.sub.3-C.sub.10
heteroaryl group, a C.sub.3-C.sub.10 heterocyclic group or a fused
C.sub.3-C.sub.10 heterocyclic group, ##STR00074## in Formula 4, A
is a substituted or unsubstituted C.sub.1-C.sub.20 heterocyclic
group, a substituted or unsubstituted C.sub.4-C.sub.20 cycloalkyl
group, or a substituted or unsubstituted C.sub.1-C.sub.20 alkyl
group; R.sub.1 through R.sub.8 are each independently a hydrogen
atom, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy
group, a C.sub.6-C.sub.20 aryl group, a C.sub.6-C.sub.20 aryloxy
group, a C.sub.1-C.sub.20 heteroaryl group, a C.sub.1-C.sub.20
heteroaryloxy group, a C.sub.4-C.sub.20 cycloalkyl group, a
C.sub.1-C.sub.20 heterocyclic group, a halogen atom, a cyano group,
or a hydroxyl group, wherein at least one of A and R.sub.1, through
R.sub.8 comprises a benzoxazine group, ##STR00075## in Formula 5,
R.sub.1 and R.sub.2 are each independently a C.sub.1-C.sub.20 alkyl
group, a C.sub.1-C.sub.20 alkoxy group, a C.sub.6-C.sub.20 aryl
group, a C.sub.6-C.sub.20 aryloxy group or a group represented by
Formula 5A below, ##STR00076## in Formulae 5 and 5A, R.sub.3 is a
hydrogen atom, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20
alkoxy group, a C.sub.6-C.sub.20 aryl group, a C.sub.6-C.sub.20
aryloxy group, a halogenated C.sub.6-C.sub.20 aryl group, a
halogenated C.sub.6-C.sub.20 aryloxy group, a C.sub.1-C.sub.20
heteroaryl group, a C.sub.1-C.sub.20 heteroaryloxy group, a
halogenated C.sub.1-C.sub.20 heteroaryl group, a halogenated
C.sub.1-C.sub.20 heteroaryloxy group, a C.sub.4-C.sub.20 carbon
ring group, a halogenated C.sub.4-C.sub.20 carbon ring group, a
C.sub.1-C.sub.20 heterocyclic group or a halogenated
C.sub.1-C.sub.20 heterocyclic group, ##STR00077## in Formula 6, at
least two adjacent groups selected from among R.sub.2, R.sub.3 and
R.sub.4 are linked to form a group represented by Formula 2A below,
and the non-selected, remaining group is a hydrogen atom, a
C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, a
C.sub.6-C.sub.20 aryl group, a C.sub.6-C.sub.20 aryloxy group, a
halogenated C.sub.6-C.sub.20 aryl group, a halogenated
C.sub.6-C.sub.20 aryloxy group, a C.sub.1-C.sub.20 heteroaryl
group, a C.sub.1-C.sub.20 heteroaryloxy group, a halogenated
C.sub.1-C.sub.20 heteroaryl group, a halogenated C.sub.1-C.sub.20
heteroaryloxy group, a C.sub.4-C.sub.20 carbon ring group, a
halogenated C.sub.4-C.sub.20 carbon ring group, a C.sub.1-C.sub.20
heterocyclic group or a halogenated C.sub.1-C.sub.20 heterocyclic
group; and at least two adjacent groups selected from among
R.sub.5, R.sub.6 and R.sub.7 are linked to form the group
represented by Formula 2A below, and the non-selected, remaining
group is a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy
group, a C.sub.6-C.sub.20 aryl group, a C.sub.6-C.sub.20 aryloxy
group, a halogenated C.sub.6-C.sub.20 aryl group, a halogenated
C.sub.6-C.sub.20 aryloxy group, a C.sub.1-C.sub.20 heteroaryl
group, a C.sub.1-C.sub.20 heteroaryloxy group, a halogenated
C.sub.1-C.sub.20 heteroaryl group, a halogenated C.sub.1-C.sub.20
heteroaryloxy group, a C.sub.4-C.sub.20 carbon ring group, a
halogenated C.sub.4-C.sub.20 carbon ring group, a C.sub.1-C.sub.20
heterocyclic group or a halogenated C.sub.1-C.sub.20 heterocyclic
group, ##STR00078## in Formula 2A, R.sub.1 is a substituted or
unsubstituted C.sub.1-C.sub.20 alkyl group, a substituted or
unsubstituted C.sub.1-C.sub.20 alkoxy group, a substituted or
unsubstituted C.sub.2-C.sub.20 alkenyl group, a substituted or
unsubstituted C.sub.2-C.sub.20 alkynyl group, a substituted or
unsubstituted C.sub.6-C.sub.20 aryl group, a substituted or
unsubstituted C.sub.6-C.sub.20 aryloxy group, a substituted or
unsubstituted C.sub.7-C.sub.20 arylalkyl group, a substituted or
unsubstituted C.sub.2-C.sub.20 heteroaryl group, a substituted or
unsubstituted C.sub.2-C.sub.20 heteroaryloxy group, a substituted
or unsubstituted C.sub.2-C.sub.20 heteroarylalkyl group, a
substituted or unsubstituted C.sub.4-C.sub.20 carbocyclic group, a
substituted or unsubstituted C.sub.4-C.sub.20 carbocyclic alkyl
group, a substituted or unsubstituted C.sub.2-C.sub.20 heterocyclic
group, or a substituted or unsubstituted C.sub.2-C.sub.20
heterocyclic alkyl group; and * denotes the sites at which the at
least two adjacent groups selected from among R.sub.2, R.sub.3 and
R.sub.4 of Formula 6 and the at least two adjacent groups selected
from among R.sub.5, R.sub.6 and R.sub.7 of Formula 6 are linked,
respectively.
8. The method of claim 7, wherein the amount of the conducting
material is in the range of about 0.25 parts to about 10 parts by
weight based on 1 parts by weight of the oxazine-based
compound.
9. The method of claim 7, further comprising processing the surface
of the metal plate before the coating of the surface of the metal
plate with the coating layer forming composition.
10. The method of claim 7, wherein the processing of the surface of
the metal plate comprises at least one process selected from the
group consisting of etching, brushing, sandpapering and
blasting.
11. The method of claim 7, wherein the thermally treating is
performed at a temperature of about 150 to about 280.degree. C.
12. A fuel cell comprising the bipolar plate according to claim
1.
13. A fuel cell comprising the bipolar plate according to claim
2.
14. A fuel cell comprising the bipolar plate according to claim
3.
15. A fuel cell comprising the bipolar plate according to claim
4.
16. A fuel cell comprising the bipolar plate according to claim
5.
17. A fuel cell comprising the bipolar plate according to claim 6.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of Korean Patent
Application No. 10-2010-0022426, filed on Mar. 12, 2010, in the
Korean Intellectual Property Office, the disclosure of which is
incorporated herein in its entirety by reference.
BACKGROUND
[0002] 1. Field
[0003] The present disclosure relates to a bipolar plate for a fuel
cell, a method of manufacturing the bipolar plate, and a fuel cell
including the bipolar plate.
[0004] 2. Description of the Related Art
[0005] Fuel cells are power generating devices producing electric
energy from chemical energy through oxidation and reduction
reactions between hydrogen and oxygen.
[0006] Fuel cells use a stack of several to hundreds of unit cells
since one unit cell has a low output voltage. In order to
electrically connect the individual unit cells in a stack, bipolar
plates are used. Bipolar plates separate different reaction gases
and also act as flow paths of cooling water.
[0007] Such a bipolar plate is a core part of fuel cells together
with a membrane-electrode assembly (MEA) and has multiple functions
that include supporting structures of the MEA and gas diffusion
layers, collecting and transferring current, transferring and
removing reaction gases, and transferring cooling water to remove
reaction heat. Therefore, there has been a demand for a bipolar
plate having excellent electrical conductivity and resistance to
corrosion.
[0008] However, currently known bipolar plates are not satisfactory
in terms of electrical conductivity and resistance to corrosion,
and thus, there is still a demand for further improvement.
SUMMARY
[0009] Provided are bipolar plates for fuel cells that have
improved resistance to corrosion, methods of manufacturing the
bipolar plates, and fuel cells including the bipolar plates.
[0010] Additional aspects will be set forth in part in the
description which follows and, in part, will be apparent from the
description, or may be learned by practice of the presented
embodiments.
[0011] According to an aspect of the present invention, a bipolar
plate for a fuel cell includes:
[0012] a metal plate; and
[0013] a coating layer disposed on a surface of the metal plate,
the coating layer including a polymer of an oxazine-based compound
and a conducting material,
[0014] wherein the oxazine-based compound includes at least one
compound selected from the compounds represented by Formulae 1
through 6 below:
##STR00001##
[0015] wherein, in Formula 1, R.sub.1 through R.sub.4 are each
independently a hydrogen atom, a substituted or unsubstituted
C1-C20 alkyl group, a substituted or unsubstituted C1-C20 alkoxy
group, a substituted or unsubstituted C2-C20 alkenyl group, a
substituted or unsubstituted C2-C20 alkynyl group, a substituted or
unsubstituted C6-C20 aryl group, a substituted or unsubstituted
C6-C20 aryloxy group, a substituted or unsubstituted C2-C20
heteroaryl group, a substituted or unsubstituted C2-C20
heteroaryloxy group, a substituted or unsubstituted C4-C20 carbon
ring group, a substituted or unsubstituted C4-C20 carbocyclic alkyl
group, a substituted or unsubstituted C2-C20 heterocyclic group, a
halogen atom, a hydroxyl group, or a cyano group; and
[0016] R.sub.5 is a substituted or unsubstituted C1-C20 alkyl
group, a substituted or unsubstituted C1-C20 alkoxy group, a
substituted or unsubstituted C2-C20 alkenyl group, a substituted or
unsubstituted C2-C20 alkynyl group, a substituted or unsubstituted
C6-C20 aryl group, a substituted or unsubstituted C6-C20 aryloxy
group, a substituted or unsubstituted C7-C20 arylalkyl group, a
substituted or unsubstituted C2-C20 heteroaryl group, a substituted
or unsubstituted C2-C20 heteroaryloxy group, a substituted or
unsubstituted C2-C20 heteroarylalkyl group, a substituted or
unsubstituted C4-C20 carbocyclic group, a substituted or
unsubstituted C4-C20 carbocyclic alkyl group, a substituted or
unsubstituted C2-C20 heterocyclic group, or a substituted or
unsubstituted C2-C20 heterocyclic alkyl group,
##STR00002##
[0017] in Formula 2, R.sub.5' is a substituted or unsubstituted
C1-C20 alkyl group, a substituted or unsubstituted C1-C20 alkoxy
group, a substituted or unsubstituted C2-C20 alkenyl group, a
substituted or unsubstituted C2-C20 alkynyl group, a substituted or
unsubstituted C6-C20 aryl group, a substituted or unsubstituted
C6-C20 aryloxy group, a substituted or unsubstituted C7-C20
arylalkyl group, a substituted or unsubstituted C2-C20 heteroaryl
group, a substituted or unsubstituted C2-C20 heteroaryloxy group, a
substituted or unsubstituted C2-C20 heteroarylalkyl group, a
substituted or unsubstituted C4-C20 carbocyclic group, a
substituted or unsubstituted C4-C20 carbocyclic alkyl group, a
substituted or unsubstituted C2-C20 heterocyclic group, or a
substituted or unsubstituted C2-C20 heterocyclic alkyl group;
and
[0018] R.sub.6 is selected from the group consisting of a
substituted or unsubstituted C1-C20 alkylene group, a substituted
or unsubstituted C2-C20 alkenylene group, a substituted or
unsubstituted C2-C20 alkynylene group, a substituted or
unsubstituted C6-C20 arylene group, a substituted or unsubstituted
C2-C20 heteroarylene group, --C(.dbd.O)--, and --SO.sub.2--,
##STR00003##
[0019] in Formula 3, A, B, C, D and E are all carbon; or one or two
of A, B, C, D and E is nitrogen and the others are carbon; and
[0020] R.sub.1 and R.sub.2 are linked to form a ring, wherein the
ring is a C6-C10 carbon ring group, a C3-C10 heteroaryl group, a
fused C3-C10 heteroaryl group, a C3-C10 heterocyclic group or a
fused C3-C10 heterocyclic group,
##STR00004##
[0021] in Formula 4, A is a substituted or unsubstituted C1-C20
heterocyclic group, a substituted or unsubstituted C4-C20
cycloalkyl group, or a substituted or unsubstituted C1-C20 alkyl
group; and
[0022] R.sub.1 through R.sub.8 are each independently a hydrogen
atom, a C1-C20 alkyl group, a C1-C20 alkoxy group, a C6-C20 aryl
group, a C6-C20 aryloxy group, a C1-C20 heteroaryl group, a C1-C20
heteroaryloxy group, a C4-C20 cycloalkyl group, a C1-C20
heterocyclic group, a halogen atom, a cyano group, or a hydroxyl
group, wherein at least one of A and R.sub.1 through R.sub.8
comprises a benzoxazine group,
##STR00005##
[0023] in Formula 5, R.sub.1 and R.sub.2 are each independently a
C1-C20 alkyl group, a C1-C20 alkoxy group, a C6-C20 aryl group, a
C6-C20 aryloxy group or a group represented by Formula 5A
below,
##STR00006##
[0024] in Formulae 5 and 5A, R.sub.3 is a hydrogen atom, a C1-C20
alkyl group, a C1-C20 alkoxy group, a C6-C20 aryl group, a C6-C20
aryloxy group, a halogenated C6-C20 aryl group, a halogenated
C6-C20 aryloxy group, a C1-C20 heteroaryl group, a C1-C20
heteroaryloxy group, a halogenated C1-C20 heteroaryl group, a
halogenated C1-C20 heteroaryloxy group, a C4-C20 carbon ring group,
a halogenated C4-C20 carbon ring group, a C1-C20 heterocyclic group
or a halogenated C1-C20 heterocyclic group.
##STR00007##
[0025] in Formula 6, at least two adjacent groups selected from
among R.sub.2, R.sub.3 and R.sub.4 are linked to form a group
represented by Formula 2A below, and the non-selected, remaining
group is a hydrogen atom, a C1-C20 alkyl group, a C1-C20 alkoxy
group, a C6-C20 aryl group, a C6-C20 aryloxy group, a halogenated
C6-C20 aryl group, a halogenated C6-C20 aryloxy group, a C1-C20
heteroaryl group, a C1-C20 heteroaryloxy group, a halogenated
C1-C20 heteroaryl group, a halogenated C1-C20 heteroaryloxy group,
a C4-C20 carbon ring group, a halogenated C4-C20 carbon ring group,
a C1-C20 heterocyclic group or a halogenated C1-C20 heterocyclic
group; and
[0026] at least two adjacent groups selected from among R.sub.5,
R.sub.6 and R.sub.7 are linked to form the group represented by
Formula 2A below, and the non-selected, remaining group is a C1-C20
alkyl group, a C1-C20 alkoxy group, a C6-C20 aryl group, a C6-C20
aryloxy group, a halogenated C6-C20 aryl group, a halogenated
C6-C20 aryloxy group, a C1-C20 heteroaryl group, a C1-C20
heteroaryloxy group, a halogenated C1-C20 heteroaryl group, a
halogenated C1-C20 heteroaryloxy group, a C4-C20 carbon ring group,
a halogenated C4-C20 carbon ring group, a C1-C20 heterocyclic group
or a halogenated C1-C20 heterocyclic group,
##STR00008##
[0027] in Formula 2A, R.sub.1 is a substituted or unsubstituted
C1-C20 alkyl group, a substituted or unsubstituted C1-C20 alkoxy
group, a substituted or unsubstituted C2-C20 alkenyl group, a
substituted or unsubstituted C2-C20 alkynyl group, a substituted or
unsubstituted C6-C20 aryl group, a substituted or unsubstituted
C6-C20 aryloxy group, a substituted or unsubstituted C7-C20
arylalkyl group, a substituted or unsubstituted C2-C20 heteroaryl
group, a substituted or unsubstituted C2-C20 heteroaryloxy group, a
substituted or unsubstituted C2-C20 heteroarylalkyl group, a
substituted or unsubstituted C4-C20 carbocyclic group, a
substituted or unsubstituted C4-C20 carbocyclic alkyl group, a
substituted or unsubstituted C2-C20 heterocyclic group, or a
substituted or unsubstituted C2-C20 heterocyclic alkyl group;
and
[0028] * denotes the sites at which the at least two adjacent
groups selected from among R2, R3 and R4 of Formula 6 and the at
least two adjacent groups selected from among R5, R6 and R7 are
linked, respectively.
[0029] According to another aspect of the present invention, a
method of manufacturing a bipolar plate for a fuel cell, the method
includes:
[0030] coating a surface of a metal plate with a coating layer
forming composition including at least one oxazine-based compound
selected from compounds represented by Formulae 1 through 6 below,
a conducting material, and a solvent; and
[0031] thermally treating the metal plate coated with the coating
layer forming composition.
##STR00009##
[0032] wherein in Formula 1, R.sub.1 through R.sub.4 are each
independently a hydrogen atom, a substituted or unsubstituted
C1-C20 alkyl group, a substituted or unsubstituted C1-C20 alkoxy
group, a substituted or unsubstituted C2-C20 alkenyl group, a
substituted or unsubstituted C2-C20 alkynyl group, a substituted or
unsubstituted C6-C20 aryl group, a substituted or unsubstituted
C6-C20 aryloxy group, a substituted or unsubstituted C2-C20
heteroaryl group, a substituted or unsubstituted C2-C20
heteroaryloxy group, a substituted or unsubstituted C4-C20 carbon
ring group, a substituted or unsubstituted C4-C20 carbocyclic alkyl
group, a substituted or unsubstituted C2-C20 heterocyclic group, a
halogen atom, a hydroxyl group, or a cyano group; and
[0033] R.sub.5 is a substituted or unsubstituted C1-C20 alkyl
group, a substituted or unsubstituted C1-C20 alkoxy group, a
substituted or unsubstituted C2-C20 alkenyl group, a substituted or
unsubstituted C2-C20 alkynyl group, a substituted or unsubstituted
C6-C20 aryl group, a substituted or unsubstituted C6-C20 aryloxy
group, a substituted or unsubstituted C7-C20 arylalkyl group, a
substituted or unsubstituted C2-C20 heteroaryl group, a substituted
or unsubstituted C2-C20 heteroaryloxy group, a substituted or
unsubstituted C2-C20 heteroarylalkyl group, a substituted or
unsubstituted C4-C20 carbocyclic group, a substituted or
unsubstituted C4-C20 carbocyclic alkyl group, a substituted or
unsubstituted C2-C20 heterocyclic group, or a substituted or
unsubstituted C2-C20 heterocyclic alkyl group,
##STR00010##
[0034] in Formula 2, R.sub.5' is a substituted or unsubstituted
C1-C20 alkyl group, a substituted or unsubstituted C1-C20 alkoxy
group, a substituted or unsubstituted C2-C20 alkenyl group, a
substituted or unsubstituted C2-C20 alkynyl group, a substituted or
unsubstituted C6-C20 aryl group, a substituted or unsubstituted
C6-C20 aryloxy group, a substituted or unsubstituted C7-C20
arylalkyl group, a substituted or unsubstituted C2-C20 heteroaryl
group, a substituted or unsubstituted C2-C20 heteroaryloxy group, a
substituted or unsubstituted C2-C20 heteroarylalkyl group, a
substituted or unsubstituted C4-C20 carbocyclic group, a
substituted or unsubstituted C4-C20 carbocyclic alkyl group, a
substituted or unsubstituted C2-C20 heterocyclic group, or a
substituted or unsubstituted C2-C20 heterocyclic alkyl group;
and
[0035] R.sub.6 is selected from the group consisting of a
substituted or unsubstituted C1-C20 alkylene group, a substituted
or unsubstituted C2-C20 alkenylene group, a substituted or
unsubstituted C2-C20 alkynylene group, a substituted or
unsubstituted C6-C20 arylene group, a substituted or unsubstituted
C2-C20 heteroarylene group, --C(.dbd.O)--, and --SO.sub.2--,
##STR00011##
[0036] in Formula 3, A, B, C, D and E are all carbon; or one or two
of A, B, C, D and E is nitrogen and the others are carbon; and
[0037] R.sub.1 and R.sub.2 are linked to form a ring, wherein the
ring is a C6-C10 cycloalkyl group, a C3-C10 heteroaryl group, a
fused C3-C10 heteroaryl group, a C3-C10 heterocyclic group or a
fused C3-C10 heterocyclic group,
##STR00012##
[0038] in Formula 4, A is a substituted or unsubstituted C1-C20
heterocyclic group, a substituted or unsubstituted C4-C20
cycloalkyl group, or a substituted or unsubstituted C1-C20 alkyl
group;
[0039] R.sub.1 through R.sub.8 are each independently a hydrogen
atom, a C1-C20 alkyl group, a C1-C20 alkoxy group, a C6-C20 aryl
group, a C6-C20 aryloxy group, a C1-C20 heteroaryl group, a C1-C20
heteroaryloxy group, a C4-C20 cycloalkyl group, a C1-C20
heterocyclic group, a halogen atom, a cyano group, or a hydroxyl
group, wherein at least one of A and R.sub.1 through R.sub.8
comprises a benzoxazine group,
##STR00013##
[0040] in Formula 5, R.sub.1 and R.sub.2 are each independently a
C1-C20 alkyl group, a C1-C20 alkoxy group, a C6-C20 aryl group, a
C6-C20 aryloxy group or a group represented by Formula 5A
below,
##STR00014##
[0041] in Formulae 5 and 5A, R.sub.3 is a hydrogen atom, a C1-C20
alkyl group, a C1-C20 alkoxy group, a C6-C20 aryl group, a C6-C20
aryloxy group, a halogenated C6-C20 aryl group, a halogenated
C6-C20 aryloxy group, a C1-C20 heteroaryl group, a C1-C20
heteroaryloxy group, a halogenated C1-C20 heteroaryl group, a
halogenated C1-C20 heteroaryloxy group, a C4-C20 carbon ring group,
a halogenated C4-C20 carbon ring group, a C1-C20 heterocyclic group
or a halogenated C1-C20 heterocyclic group,
##STR00015##
[0042] in Formula 6, at least two adjacent groups selected from
among R.sub.2, R.sub.3 and R.sub.4 are linked to form a group
represented by Formula 2A below, and the non-selected, remaining
group is a hydrogen atom, a C1-C20 alkyl group, a C1-C20 alkoxy
group, a C6-C20 aryl group, a C6-C20 aryloxy group, a halogenated
C6-C20 aryl group, a halogenated C6-C20 aryloxy group, a C1-C20
heteroaryl group, a C1-C20 heteroaryloxy group, a halogenated
C1-C20 heteroaryl group, a halogenated C1-C20 heteroaryloxy group,
a C4-C20 carbon ring group, a halogenated C4-C20 carbon ring group,
a C1-C20 heterocyclic group or a halogenated C1-C20 heterocyclic
group; and
[0043] at least two adjacent groups selected from among R.sub.5,
R.sub.6 and R.sub.7 are linked to form the group represented by
Formula 2A below, and the non-selected, remaining group is a C1-C20
alkyl group, a C1-C20 alkoxy group, a C6-C20 aryl group, a C6-C20
aryloxy group, a halogenated C6-C20 aryl group, a halogenated
C6-C20 aryloxy group, a C1-C20 heteroaryl group, a C1-C20
heteroaryloxy group, a halogenated C1-C20 heteroaryl group, a
halogenated C1-C20 heteroaryloxy group, a C4-C20 carbon ring group,
a halogenated C4-C20 carbon ring group, a C1-C20 heterocyclic group
or a halogenated C1-C20 heterocyclic group,
##STR00016##
[0044] in Formula 2A, R.sub.1 is a substituted or unsubstituted
C1-C20 alkyl group, a substituted or unsubstituted C1-C20 alkoxy
group, a substituted or unsubstituted C2-C20 alkenyl group, a
substituted or unsubstituted C2-C20 alkynyl group, a substituted or
unsubstituted C6-C20 aryl group, a substituted or unsubstituted
C6-C20 aryloxy group, a substituted or unsubstituted C7-C20
arylalkyl group, a substituted or unsubstituted C2-C20 heteroaryl
group, a substituted or unsubstituted C2-C20 heteroaryloxy group, a
substituted or unsubstituted C2-C20 heteroarylalkyl group, a
substituted or unsubstituted C4-C20 carbocyclic group, a
substituted or unsubstituted C4-C20 carbocyclic alkyl group, a
substituted or unsubstituted C2-C20 heterocyclic group, or a
substituted or unsubstituted C2-C20 heterocyclic alkyl group;
and
[0045] *denotes the sites at which the at least two adjacent groups
selected from
[0046] among R.sub.2, R.sub.3 and R.sub.4 of Formula 6 and the at
least two adjacent groups selected from among R.sub.5, R.sub.6 and
R.sub.7 are linked, respectively.
[0047] According to another aspect of the present invention, a fuel
cell includes the bipolar plate.
BRIEF DESCRIPTION OF THE DRAWINGS
[0048] These and/or other aspects and advantages of the invention
will become apparent and more readily appreciated from the
following description of the embodiments, taken in conjunction with
the accompanying drawings of which:
[0049] FIG. 1 is a cross-sectional view of a bipolar plate for a
fuel cell, according to an embodiment of the present
disclosure;
[0050] FIG. 2 is a graph illustrating resistance characteristics of
bipolar plates for a fuel cell manufactured according to Examples
1-1 to 1-3 with respect to applied pressure;
[0051] FIG. 3 is a graph illustrating resistance characteristics of
bipolar plates for a fuel cell manufactured according to Examples
2-1 to 2-3 with respect to applied pressure;
[0052] FIG. 4 is a graph illustrating resistance characteristics of
bipolar plates for a fuel cell manufactured according to Examples
3-1 to 3-5 with respect to applied pressure;
[0053] FIG. 5 is a graph illustrating resistance characteristics of
bipolar plates for a fuel cell manufactured according to
Comparative Examples 1 through 3 with respect to applied
pressure;
[0054] FIG. 6 is a graph illustrating the results of a test of
resistance to acid performed on bipolar plates for a fuel cell
manufactured according to Examples 2-1 and 2-2 and Comparative
Examples 1 and 2;
[0055] FIG. 7 is a graph illustrating resistance characteristics of
bipolar plates for a fuel cell according to Examples 4-1 through
4-4 with respect to applied pressure;
[0056] FIG. 8 is an exploded perspective view of a fuel cell
according to an embodiment of the present disclosure; and
[0057] FIG. 9 is a cross-sectional diagram of a membrane-electrode
assembly included in the fuel cell of FIG. 8.
DETAILED DESCRIPTION
[0058] Reference will now be made in detail to embodiments,
examples of which are illustrated in the accompanying drawings,
wherein like reference numerals refer to the like elements
throughout. In this regard, the present embodiments may have
different forms and should not be construed as being limited to the
descriptions set forth herein. Accordingly, the embodiments are
merely described below, by referring to the figures, to explain
aspects of the present description.
[0059] According to an aspect of the present invention, a bipolar
plate for a fuel cell includes a metal plate and a coating layer
disposed on a surface of the metal plate, the coating layer
including a polymer of an oxazine-based compound, particularly a
benzoxazine compound, and a conducting material.
[0060] The polymer of the oxazine-based compound, which is coated
on the surface of the metal layer together with the conducting
material, is resistant to acid. Thus, the bipolar plate has
excellent electrical conductivity, has good excellent resistance to
acid, and improved resistance to corrosion.
[0061] The oxazine-based compound includes at least one compound
selected from the compounds represented by Formulae 1 through 6
below:
##STR00017##
[0062] In Formula 1, R.sub.1 through R.sub.4 are each independently
a hydrogen atom, a substituted or unsubstituted C.sub.1-C.sub.20
alkyl group, a substituted or unsubstituted C.sub.1-C.sub.20 alkoxy
group, a substituted or unsubstituted C.sub.2-C.sub.20 alkenyl
group, a substituted or unsubstituted C.sub.2-C.sub.20 alkynyl
group, a substituted or unsubstituted C.sub.6-C.sub.20 aryl group,
a substituted or unsubstituted C.sub.6-C.sub.20 aryloxy group, a
substituted or unsubstituted C.sub.2-C.sub.20 heteroaryl group, a
substituted or unsubstituted C.sub.2-C.sub.20 heteroaryloxy group,
a substituted or unsubstituted C.sub.4-C.sub.20 carbon ring group,
a substituted or unsubstituted C.sub.4-C.sub.20 carbocyclic alkyl
group, a substituted or unsubstituted C.sub.2-C.sub.20 heterocyclic
group, a halogen atom, a hydroxyl group, or a cyano group; and
[0063] R.sub.5 is a substituted or unsubstituted C.sub.1-C.sub.20
alkyl group, a substituted or unsubstituted C.sub.1-C.sub.20 alkoxy
group, a substituted or unsubstituted C.sub.2-C.sub.20 alkenyl
group, a substituted or unsubstituted C.sub.2-C.sub.20 alkynyl
group, a substituted or unsubstituted C.sub.6-C.sub.20 aryl group,
a substituted or unsubstituted C.sub.6-C.sub.20 aryloxy group, a
substituted or unsubstituted C.sub.7-C.sub.20 arylalkyl group, a
substituted or unsubstituted C.sub.2-C.sub.20 heteroaryl group, a
substituted or unsubstituted C.sub.2-C.sub.20 heteroaryloxy group,
a substituted or unsubstituted C.sub.2-C.sub.20 heteroarylalkyl
group, a substituted or unsubstituted C.sub.4-C.sub.20 carbocyclic
group, a substituted or unsubstituted C.sub.4-C.sub.20 carbocyclic
alkyl group, a substituted or unsubstituted C.sub.2-C.sub.20
heterocyclic group, or a substituted or unsubstituted
C.sub.2-C.sub.20 heterocyclic alkyl group,
##STR00018##
[0064] In Formula 2, R.sub.5 is a substituted or unsubstituted
C.sub.1-C.sub.20 alkyl group, a substituted or unsubstituted
C.sub.1-C.sub.20 alkoxy group, a substituted or unsubstituted
C.sub.2-C.sub.20 alkenyl group, a substituted or unsubstituted
C.sub.2-C.sub.20 alkynyl group, a substituted or unsubstituted
C.sub.6-C.sub.20 aryl group, a substituted or unsubstituted
C.sub.6-C.sub.20 aryloxy group, a substituted or unsubstituted
C.sub.7-C.sub.20 arylalkyl group, a substituted or unsubstituted
C.sub.2-C.sub.20 heteroaryl group, a substituted or unsubstituted
C.sub.2-C.sub.20 heteroaryloxy group, a substituted or
unsubstituted C.sub.2-C.sub.20 heteroarylalkyl group, a substituted
or unsubstituted C.sub.4-C.sub.20 carbocyclic group, a substituted
or unsubstituted C.sub.4-C.sub.20 carbocyclic alkyl group, a
substituted or unsubstituted C.sub.2-C.sub.20 heterocyclic group,
or a substituted or unsubstituted C.sub.2-C.sub.20 heterocyclic
alkyl group; and
[0065] R.sub.6 is selected from the group consisting of a
substituted or unsubstituted alkylene group, a substituted or
unsubstituted C.sub.2-C.sub.20 alkenylene group, a substituted or
unsubstituted C.sub.2-C.sub.20 alkynylene group, a substituted or
unsubstituted C.sub.6-C.sub.20 arylene group, a substituted or
unsubstituted C.sub.2-C.sub.20 heteroarylene group, --C(.dbd.O)--,
and --SO.sub.2--.
##STR00019##
[0066] In Formula 3, A, B, C, D and E are all carbon; or one or two
of A, B, C, D and E is nitrogen and the others are carbon, and
R.sub.1 and R.sub.2 are linked to form a ring, wherein the ring is
a C.sub.6-C.sub.10 carbon ring group, a C.sub.3-C.sub.10 heteroaryl
group, a fused C.sub.3-C.sub.10 heteroaryl group, a
C.sub.3-C.sub.10 heterocyclic group or a fused C.sub.3-C.sub.10
heterocyclic group.
##STR00020##
[0067] In Formula 4, A is a substituted or unsubstituted
C.sub.1-C.sub.20 heterocyclic group, a substituted or unsubstituted
C.sub.4-C.sub.20 cycloalkyl group, or a substituted or
unsubstituted C.sub.1-C.sub.20 alkyl group; and
R.sub.1 through R.sub.8 are each independently a hydrogen atom, a
C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, a
C.sub.6-C.sub.20 aryl group, a C.sub.6-C.sub.20 aryloxy group, a
C.sub.1-C.sub.20 heteroaryl group, a C.sub.1-C.sub.20 heteroaryloxy
group, a C.sub.4-C.sub.20 cycloalkyl group, a C.sub.1-C.sub.20
heterocyclic group, a halogen atom, a cyano group, or a hydroxyl
group, wherein at least one of A and R.sub.1 through R.sub.8
comprises a benzoxazine group.
##STR00021##
[0068] In Formula 5, R.sub.1 and R.sub.2 are each independently a
C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, a
C.sub.6-C.sub.20 aryl group, a C.sub.6-C.sub.20 aryloxy group or a
group represented by Formula 5A below.
##STR00022##
[0069] In Formulae 5 and 5A, R.sub.3 is a hydrogen atom, a
C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, a
C.sub.6-C.sub.20 aryl group, a C.sub.6-C.sub.20 aryloxy group, a
halogenated C.sub.6-C.sub.20 aryl group, a halogenated
C.sub.6-C.sub.20 aryloxy group, a C.sub.1-C.sub.20 heteroaryl
group, a C.sub.1-C.sub.20 heteroaryloxy group, a halogenated
C.sub.1-C.sub.20 heteroaryl group, a halogenated C.sub.1-C.sub.20
heteroaryloxy group, a C.sub.4-C.sub.20 carbon ring group, a
halogenated C.sub.4-C.sub.20 carbon ring group, a C.sub.1-C.sub.20
heterocyclic group or a halogenated C.sub.1-C.sub.20 heterocyclic
group.
##STR00023##
[0070] In Formula 6, at least two adjacent groups selected from
among R.sub.2, R.sub.3 and R.sub.4 are linked to form a group
represented by Formula 2A below, and the non-selected, remaining
group is a hydrogen atom, a C.sub.1-C.sub.20 alkyl group, a
C.sub.1-C.sub.20 alkoxy group, a C.sub.6-C.sub.20 aryl group, a
C.sub.6-C.sub.20 aryloxy group, a halogenated C.sub.6-C.sub.20 aryl
group, a halogenated C.sub.6-C.sub.20 aryloxy group, a
C.sub.1-C.sub.20 heteroaryl group, a C.sub.1-C.sub.20 heteroaryloxy
group, a halogenated C.sub.1-C.sub.20 heteroaryl group, a
halogenated C.sub.1-C.sub.20 heteroaryloxy group, a
C.sub.4-C.sub.20 carbon ring group, a halogenated C.sub.4-C.sub.20
carbon ring group, a C.sub.1-C.sub.20 heterocyclic group or a
halogenated C.sub.1-C.sub.20 heterocyclic group; and
at least two adjacent groups selected from among R.sub.5, R.sub.6
and R.sub.7 are linked to form the group represented by Formula 2A
below, and the non-selected, remaining group is a C.sub.1-C.sub.20
alkyl group, a C.sub.1-C.sub.20 alkoxy group, a C.sub.6-C.sub.20
aryl group, a C.sub.6-C.sub.20 aryloxy group, a halogenated
C.sub.6-C.sub.20 aryl group, a halogenated C.sub.6-C.sub.20 aryloxy
group, a C.sub.1-C.sub.20 heteroaryl group, a C.sub.1-C.sub.20
heteroaryloxy group, a halogenated C.sub.1-C.sub.20 heteroaryl
group, a halogenated C.sub.1-C.sub.20 heteroaryloxy group, a
C.sub.4-C.sub.20 carbon ring group, a halogenated C.sub.4-C.sub.20
carbon ring group, a C.sub.1-C.sub.20 heterocyclic group or a
halogenated C.sub.1-C.sub.20 heterocyclic group.
##STR00024##
[0071] In Formula 2A, R.sub.1 is a substituted or unsubstituted
C.sub.1-C.sub.20 alkyl group, a substituted or unsubstituted
C.sub.1-C.sub.20 alkoxy group, a substituted or unsubstituted
C.sub.2-C.sub.20 alkenyl group, a substituted or unsubstituted
C.sub.2-C.sub.20 alkynyl group, a substituted or unsubstituted
C.sub.6-C.sub.20 aryl group, a substituted or unsubstituted
C.sub.6-C.sub.20 aryloxy group, a substituted or unsubstituted
C.sub.7-C.sub.20 arylalkyl group, a substituted or unsubstituted
C.sub.2-C.sub.20 heteroaryl group, a substituted or unsubstituted
C.sub.2-C.sub.20 heteroaryloxy group, a substituted or
unsubstituted C.sub.2-C.sub.20 heteroarylalkyl group, a substituted
or unsubstituted C.sub.4-C.sub.20 carbocyclic group, a substituted
or unsubstituted C.sub.4-C.sub.20 carbocyclic alkyl group, a
substituted or unsubstituted C.sub.2-C.sub.20 heterocyclic group,
or a substituted or unsubstituted C.sub.2-C.sub.20 heterocyclic
alkyl group; and
* denotes the sites at which the at least two adjacent groups
selected from among R.sub.2, R.sub.3 and R.sub.4 of Formula 6 and
the at least two adjacent groups selected from among R.sub.5,
R.sub.6 and R.sub.7 of Formula 6 are linked, respectively.
[0072] In Formula 2A, R.sub.1 is selected from the groups
represented by the following formulae.
##STR00025##
[0073] It is to be understood that in all of the formulae provided
herein, substituents such as R.sub.1, R.sub.2, etc. are not
universally defined. Instead, particular definitions for these
substituents are provided for each specific formula or groups of
related formulae, as indicated.
[0074] Examples of the benzoxazine-based monomer of Formula 1 may
include compounds represented by the following formulae.
##STR00026## ##STR00027## ##STR00028## ##STR00029## ##STR00030##
##STR00031## ##STR00032##
[0075] Examples of the benzoxazine-based monomer of Formula 2 may
include compounds represented by the following formulae.
##STR00033##
[0076] In the formulae above, R.sub.2 is a phenyl group,
--CH.sub.2--CH.dbd.CH.sub.2, or one of the groups represented by
the following formulae:
##STR00034##
[0077] For example, the compound of Formula 2 may be selected from
the compounds represented by the following formulae:
##STR00035##
[0078] Examples of the oxazine-based monomer of Formula 3 may
include compounds represented by the following formulae.
##STR00036##
[0079] In Formula 3A, R is a hydrogen atom or a C.sub.1-C.sub.10
alkyl group.
##STR00037##
[0080] In Formula 3 above,
##STR00038##
is selected from the groups represented by the following
formulae.
##STR00039##
[0081] Specific examples of the oxazine-based monomer of Formula 3
may include compounds represented by the following formulae.
##STR00040## ##STR00041## ##STR00042##
[0082] Examples of the benzoxazine-based monomer of Formula 4
include compounds represented by the following formulae.
[0083] In Formula 4, A may be selected from the groups represented
by Formulae 4A and 4B below.
##STR00043##
[0084] In Formulae 4A and 4B, R.sub.1 is a hydrogen atom, a
C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, a
C.sub.6-C.sub.20 aryl group, a C.sub.6-C.sub.20 aryloxy group, a
halogenated C.sub.6-C.sub.20 aryl group, a halogenated
C.sub.6-C.sub.20 aryloxy group, a C.sub.1-C.sub.20 heteroaryl
group, a C.sub.1-C.sub.20 heteroaryloxy group, a halogenated
C.sub.1-C.sub.20 heteroaryl group, a halogenated C.sub.1-C.sub.20
heteroaryloxy group, a C.sub.4-C.sub.20 carbon ring group, a
halogenated C.sub.4-C.sub.20 carbon ring group, a C.sub.1-C.sub.20
heterocyclic group or a halogenated C.sub.1-C.sub.20 heterocyclic
group.
[0085] Examples of the benzoxazine-based monomer of Formula 4
containing phosphorous include compounds represented by Formulae 4C
and 4D below.
##STR00044##
[0086] In Formulae 4C and 4D, R.sub.1 may be selected from the
groups represented by the following formulae.
##STR00045##
[0087] Specific examples of the benzoxazine-based monomer of
Formula 4 include the compounds represented by the following
formulae:
##STR00046## ##STR00047##
[0088] Examples of the benzoxazine-based monomer of Formula 5
include compounds represented by Formulae 5B, 5C and 5D below.
##STR00048##
[0089] In Formulae 5B and 5C, R.sub.2 is a C.sub.1-C.sub.10 alkyl
group, a C.sub.1-C.sub.10 alkoxy group, a C.sub.6-C.sub.10 aryl
group, or a C.sub.6-C.sub.10 aryloxy group; and R.sub.3 is selected
from the groups represented by the following formulae:
##STR00049##
[0090] In Formula 5D, R.sub.4 and R.sub.5 are each independently a
C.sub.6-C.sub.10 aryl group; and R.sub.3 is selected from the
groups represented by the following formulae:
##STR00050##
[0091] Examples of the compound of Formula 5 include compounds
represented by Formulae 5E and 5F below:
##STR00051##
[0092] In Formulae 5E and 5F, R.sub.3 is selected from the groups
represented by the following formulae.
##STR00052##
[0093] Specific examples of the benzoxazine-based monomer of
Formula 5 include compounds represented by the following
formulae.
##STR00053## ##STR00054##
[0094] Examples of the benzoxazine-based monomer of Formula 6
include compounds represented by Formulae 6A through 6C.
##STR00055##
[0095] In Formulae 6A through 6C, R.sub.1 is selected from the
groups represented by the following formulae.
##STR00056##
[0096] Specific examples of the benzoxazine-based monomer of
Formula 6 include compounds represented by the following
formulae.
##STR00057## ##STR00058##
[0097] The oxazine-based compound may be at least one compound
selected from the group consisting of a compound (t-BuPh) of
Formula 7, a compound (t-PPO-a) of Formula 8, a compound
(4-DFPh-4AP) of Formula 9, a compound (HF-a) of Formula 10, a
compound (27-DHN-34DFA) of Formula 11, a compound (3,4-DFPh-4FA) of
Formula 12, a compound (3HP-2AP) of Formula 13, and a compound
(BPS-A) of Formula 14.
##STR00059## ##STR00060##
[0098] The conducting material in the coating layer may include a
carbonaceous material having a specific surface area of about 60 to
about 250 m.sup.2/g, and an average particle diameter of about 0.1
to about 10 um.
[0099] The conducting material may be, for example, at least one
material selected from the group consisting of carbon black,
graphite and carbon nanotubes.
[0100] Examples of the conducting material include MCMB (Osaka
gas), Vulcan XC-72 (Cabot Corporation) and Timrex (Timcal Graphite
& Carbon), which are commercially available.
[0101] In this regard, "MCMB" is the product name of a microcarbon
microbead, "Vulcan XC-72" is the product name a carbon black,
"Timrex" is a product name of a graphite. In particular, the term
"Timrex" as used in the examples herein refers to Timrex HSAG 300
graphite.
[0102] The amount of the conducting agent in the coating layer may
be in the range of about 0.25 to about 10 parts by weight, for
example, about 0.5 to about 2 parts by weight, based on 1 part by
weight of the polymer of the benzoxazine-based compound. When the
amount of the conducting material is within this range, resistance
to corrosion and electrical conductivity of the bipolar plate may
be excellent.
[0103] FIG. 1 is a sectional view of a bipolar plate 10 for a fuel
cell, according to an embodiment of the present disclosure.
[0104] Referring to FIG. 1, the bipolar plate 10 includes a metal
plate 11 and a coating layer 14 disposed on a surface of the metal
plate 11.
[0105] The coating layer 14 may have a thickness of about 1 to
about 100 .mu.m.
[0106] The coating layer 14 may include a polymer 12 of a
benzoxazine-based compound and a conducting material 13. Herein,
the polymer 12 of the benzoxazine-based compound may act as a
binder of the conducting material 13 and the metal plate 11 and may
also prevent a contact between the metal plate 11 and acid.
[0107] The conducting material 13 facilitates electrical conduction
and minimizes contact resistance between the metal plate 11 and a
gas diffusion layer disposed on the metal plate 11. The metal plate
11 is an electrically conductive support including a path for
supplying gas.
[0108] The metal plate 11 may be formed using any substrate made of
a conductive metal or an alloy thereof. For example, the metal
plate 11 may be formed using a stainless steel plate, an aluminum
plate, a carbon steel plate, or the like.
[0109] The metal plate 11 may have a thickness of about 1 mm to
about 5 mm.
[0110] Although not illustrated in FIG. 1, the metal plate 11 may
have one or more grooves.
[0111] Hereinafter, a method of manufacturing the bipolar plate for
a fuel cell, according to an embodiment of the present disclosure,
will be described.
[0112] Initially, a metal plate is optionally subjected to a
surface process.
[0113] Impurities and an oxide film are removed from a surface of
the metal plate through the surface process. Furthermore, grooves
may be formed in the surface of the metal plate as a result of the
surface process, thereby enlarging the surface area of the metal
plate, enhancing the binding force to the coating layer on the
metal plate, and reducing contact resistance.
[0114] The surface process may include at least one process
selected from the group consisting of etching, brushing,
sandpapering and blasting.
[0115] Etching may be performed using an etching solution, for
example, about 5 to 50% sulfuric acid solution.
[0116] The metal plate, after the etching, is washed with water and
then dried until the liquid is completely removed from the surface
of the metal plate. An oxide film may be removed from the surface
of the metal plate through the etching process.
[0117] Brushing is a process of forming grooves in the surface of
the metal plate by brushing the surface with a steel brush or
like.
[0118] Sandpapering is a process of forming grooves in the surface
of the metal plate by rubbing with sandpaper at an appropriate
force.
[0119] Blasting is a process of treating the surface of the metal
plate by jetting a fine powder, such as alumina (Al.sub.2O.sub.3),
glass beads, or ceramic beads, against the surface of the metal
plate at a high pressure.
[0120] As a result of the surface process, a groove having a depth
and a width, each ranging from about 5 to about 20 .mu.m, may be
formed in the metal plate. For example, a groove having a depth and
a width with about 5, 10, or 20 .mu.m may be formed.
[0121] The groove may be formed as, for example, a matrix.
[0122] The metal plate including the groove formed through the
surface process has a larger surface area than a metal plate
without any groove. The formed grooves may enhance the binding
force of the metal plate to the coating layer.
[0123] The surface of the metal plate treated as described above is
coated with a coating layer forming composition including an
oxazine-based compound, a conducting material and a solvent to form
a coating layer.
[0124] The amount of the conducting material may be in the range of
about 0.25 to about 10 parts by weight, for example, about 1 to
about 4 parts by weight, based on 1 part by weight of the
oxazine-based compound.
[0125] When the amount of the conducting material is within this
range, electrical conductivity and resistance to corrosion of the
bipolar plate may be excellent.
[0126] The solvent may be an organic solvent, such as
N,N-dimethylacetamide (DMAC), N,N-dimethylformamide (DMF), or the
like, which may be used alone or in combination.
[0127] The amount of the solvent may be in the range of about 300
to about 1000 parts by weight based on 100 parts by weight of the
oxazine-based compound. When the amount of the solvent is within
this range, it may be easier to coat the coating layer forming
composition.
[0128] The coating of the coating layer forming composition may be
performed using spray coating, dip coating, roll coating, Pape
casting or the like.
[0129] After the coating process, a drying process may be
performed, for example, at a temperature of about 40 to about
80.degree. C.
[0130] After the coating and drying processes, the metal plate with
the dried coating layer is thermally treated, thereby completing
the manufacture of the bipolar plate for a fuel cell that includes
the polymer of the oxazine-based compound and the conducting
material.
[0131] The oxazine-based compound is polymerized through the
thermal treatment, thereby resulting in the polymer of the
oxazine-based compound in the coating layer.
[0132] The thermal treatment may be performed at a temperature of
about 150 to 280.degree. C., for example, at a temperature of about
190 to about 260.degree. C. When the temperature of the thermal
treatment is within this range, polymerization reactivity of the
oxazine-based compound may be excellent.
[0133] The duration of the thermal treatment may vary according to
the temperature of the thermal treatment. For example, the duration
of the thermal treatment may be in the range of about 1 to about 5
hours.
[0134] The bipolar plate for a fuel cell manufactured as described
above has excellent corrosion current and contact resistance
characteristics in a wide range of temperatures and may be
manufactured on a large scale at lower costs.
[0135] A fuel cell including the bipolar plate for a fuel cell may
be manufactured using general methods.
[0136] FIG. 8 is a perspective exploded view of a fuel cell 8
according to an embodiment of the present disclosure. FIG. 9 is a
cross-sectional diagram of a membrane-electrode assembly (MEA) of
the fuel cell of FIG. 8.
[0137] Referring to FIG. 8, the fuel cell 8 includes two unit cells
81 that are supported by a pair of holders 82. Each of the unit
cells 81 includes an MEA 80, and bipolar plates 90 respectively
disposed on opposite sides of the MEA 10 in the thickness direction
thereof, wherein each of the bipolar plates 90 includes a metal
plate and a coating layer that is disposed on a surface of the
metal plate and includes a polymer of a oxazine-based compound and
a conducting agent, as in an embodiment of the present disclosure
described above. The bipolar plates 90, which are bound to the MEA
80, function as current collectors, and at the same time provide
oxygen and fuel to catalyst layers of the MEAs 80.
[0138] Although only two unit cells 81 are illustrated in FIG. 8,
the number of unit cells is not limited to two and a fuel cell may
have several tens or hundreds of unit cells, depending on the
desired properties of the fuel cell.
[0139] As shown in FIG. 9, the MEA 80 includes an electrolyte
membrane 100, catalyst layers 110 and 110' disposed on lateral
sides of the electrolyte membrane 100, and first gas diffusion
layers 121 and 121' respectively stacked on the catalyst layers 110
and 110', and second gas diffusion layers 120 and 120' respectively
stacked on the first gas diffusion layers 121 and 121'.
[0140] The catalyst layers 110 and 110' function as a fuel
electrode and an oxygen electrode, respectively, and each includes
a catalyst and a binder therein. The catalyst layers 110 and 110'
may further include a material that may increase the
electrochemical surface area of the catalyst.
[0141] The first gas diffusion layers 121 and 121' and the second
gas diffusion layers 120 and 120' may each be formed of a material
such as, for example, carbon sheet or carbon paper. The first gas
diffusion layers 121 and 121' and the second gas diffusion layers
120 and 120' diffuse oxygen and fuel supplied through the bipolar
plates 90 into the entire surfaces of the catalyst layers 110 and
110'. It is to be understood that the number and positioning of
catalyst layers and diffusion layers may differ from what is shown
in FIG. 9 and that other layers may be present.
[0142] The fuel cell 8 including the MEA 80 may operate at a
temperature of 100 to 300.degree. C. Fuel such as hydrogen is
supplied through one of the bipolar plates 90 into a first catalyst
layer, and an oxidant such as oxygen is supplied through the other
bipolar plate 90 into a second catalyst layer. Then, hydrogen is
oxidized into protons in the first catalyst layer, and the protons
are conducted to the second catalyst layer through the electrolyte
membrane 100. Then, the protons electrochemically react with oxygen
in the second catalyst layer to produce water and generate
electrical energy. Moreover, the hydrogen that is supplied as a
fuel may be hydrogen that is produced by reforming hydrocarbons or
alcohols. Oxygen supplied as an oxidant may be supplied in the form
of air.
[0143] Substituents in the formulae above may be defined as
follows.
[0144] Examples of the alkyl group referred to herein include, but
are not limited to, a methyl group, an ethyl group, a propyl group,
an isobutyl group, a sec-butyl group, a pentyl group, an iso-amyl
group, and a hexyl group, wherein at least one hydrogen atom of the
alkyl group may be substituted with a substituent such as a halogen
atom, a C1-C20 alkyl group substituted with a halogen atom (for
example, CCF.sub.3, CHCF.sub.2, CH.sub.2F and CCl.sub.3), a
hydroxyl group, a nitro group, a cyano group, an amino group, an
amidino group, a hydrazine, a hydrazone, a carboxyl group or a salt
thereof, a sulfonic acid group or a salt thereof, a phosphoric acid
or a salt thereof, a C1-C20 alkyl group, a C2-C20 alkenyl group, a
C2-C20 alkynyl group, a C1-C20 heteroalkyl group, a C6-C20 aryl
group, a C6-C20 arylalkyl group, a C6-C20 heteroaryl group or a
C6-C20 heteroarylalkyl group.
[0145] Examples of the alkoxy group referred to herein include a
methoxy group, an ethoxy group, and a propoxy group. At least one
hydrogen atom in the alkoxy group may be substituted with a same
substituent as described above with respect to the alkyl group.
[0146] Examples of the alkenyl group referred to herein include
vinylene and allylene. At least one hydrogen atom in the alkenyl
group may be substituted with a same substituent as described above
with respect to the alkyl group.
[0147] An example of the alkynyl group used herein includes
acetylene. At least one hydrogen atom in the alkynyl group may be
substituted with a same substituent as described above with respect
to the alkyl group.
[0148] The aryl group referred to herein may be used alone or in
combination. In particular, the term "aryl group" refers to an
aromatic system containing at least one ring. Examples of the aryl
group include a phenyl group, a naphthyl group, a
tetrahydronaphthyl group, and the like. At least one hydrogen atom
of the aryl group may be substituted with a same substituent as
described above with respect to the alkyl group.
[0149] An example of the aryloxy group referred to herein includes
a phenoxy group. At least one hydrogen atom in the aryloxy group
may be substituted with a same substituent as described above with
respect to the alkyl group.
[0150] The term "heteroaryl group" used in the Formulae above
refers to an aromatic organic compound that includes at least one
heteroatom selected from among nitrogen (N), oxygen (O),
phosphorous (P) and sulfur (S) and remaining ring atoms of C. At
least one hydrogen atom of the heteroaryl group may be substituted
with a substituent described above with respect to the alkyl
group.
[0151] The term "carbon ring group" used herein refers to a cyclic
group exclusively including carbon atoms, such as a cyclohexyl
group. At least one hydrogen atom in the carbon ring group may be
substituted with a same substituent as described above with respect
to the alkyl group.
[0152] The term "heterocyclic group" used herein refers to a cyclic
group including a heteroatom such as N, S, P, or O. An example of
the heterocyclic group is pyridyl. At least one hydrogen atom in
the heterocyclic group may be substituted with a same substituent
as described above with respect to the alkyl group.
[0153] Examples of the halogen atom referred to herein include a
fluorine atom, a chlorine atom, a bromine atom, and the like. The
term "halogenated" used to define substituents herein means that a
substituent includes a halogen atom, such as a fluorine, chlorine,
or bromine atom, or includes an organic group containing a halogen
atom. In this regard, an example of the organic group is a C1-C20
alkyl group.
[0154] With regard to the arylene group, the heteroarylene group,
the heteroaryloxy group, the carbon ring group, the heterocyclic
alkyl group, the carbocyclic alkyl group, and the heteroarylalkyl
used herein, at least one hydrogen atom of these groups may be
substituted with a same substituent as described above with respect
to the alkyl group.
[0155] Hereinafter, one or more embodiments of the present
invention will be described in detail with reference to the
following examples. These examples are not intended to limit the
purpose and scope of the one or more embodiments of the present
invention.
Example 1-1
Manufacture of Bipolar Plate by Using a Mixture of BPS-a and Timrex
in a Weight Ratio of 1:2 and Metal Plate
[0156] 3.5 g of N,N-dimethylacetamide was added to 0.85 g of BPS-a
of Formula 14 as a solvent and then stirred. The mixture was heated
to 40-50.degree. C. to prepare a BPS-a solution.
[0157] 1.7 g of Timrex as conducting carbon was added to the BPS-a
solution and mixed for 1 hour to obtain a slurry for forming a
coating layer. Herein, BPS-a and Timrex were mixed in a weight
ratio of 1:2.
[0158] The coating layer forming slurry was coated on a stainless
steel plate having a thickness of 1.2 mm to a thickness of about 50
.mu.M by using tape casting.
[0159] The metal plate coated with the coating layer forming slurry
was dried in a 100.degree. C.-oven for 4 hours to remove the
solvent.
[0160] Then, the resulting metal plate was thermally treated at
250.degree. C. to form a coating layer containing a polymer of
BPS-a and Timrex on the metal plate, thereby completing the
manufacture of a bipolar plate for a fuel cell.
Example 1-2
Manufacture of Bipolar Plate by Using a Mixture of BPS-a and Timrex
in a Weight Ratio of 1:2 and Stainless Steel Plate Having Grooves
of about 5 .mu.m in Width and Depth
[0161] A bipolar plate for a fuel cell was manufactured in the same
manner as in Example 1-1, except that grooves of about 5 .mu.m in
width and depth were formed in the metal plate prior to coating the
coating layer forming slurry on the surface of the stainless steel
plate.
[0162] Herein, the grooves of about 5 .mu.m in width and depth were
formed by sandpapering.
[0163] In the sandpapering, initially the surface of the metal
plate was rubbed with a smooth sandpaper (cw-400, cw-1000 or
cw-2000, available from Daesung Abrasive Co., Ltd. of Korea) about
1000 to 2000 times for about 3 to 5 minutes to remove impurities
such as an oxide film, and then the surface was rubbed with a
slightly rough sandpaper about 400 times for about 5 to 10 minutes
to form the grooves. The surface of the metal plate was locally
rubbed periodically in different directions to form grooves without
any pattern extending in any direction over the entire surface of
the metal plate.
Example 1-3
Manufacture of Bipolar Plate by Using a Mixture of BPS-a and Timrex
in a Weight Ratio of 1:2 and Stainless Steel Plate Having Grooves
of about 20 .mu.m in Width and Depth
[0164] A bipolar plate for a fuel cell was manufactured in the same
manner as in Example 1-1, except that grooves of about 20 .mu.m in
width and depth were formed in the metal plate prior to coating the
coating layer forming slurry on the surface of the stainless steel
plate.
[0165] The grooves of about 20 .mu.m in width and depth were formed
by further abrading the surface of a metal plate including grooves
of about 5 .mu.m in width and depth with a more rough sandpaper.
The sandpapering with the sandpaper was performed in the same
manner as when forming the grooves of about 5 .mu.m in Example 1-2.
Alternatively, a file or a rasp may be used, instead of the
sandpaper. In this regard, the grooves may be formed in the same
manner as when to form the grooves of 5 .mu.m in Example 1-2.
[0166] Electric resistance characteristics of the bipolar plates of
Examples 1-1 to 1-3 with respect to applied pressure were evaluated
using an in-house manufactured electric resistance measuring
device. The electric resistance measuring device included a
pressing device for fixing a sample whose resistance was to be
measured and a measurement and control unit for measuring
resistance while applying current and controlling pressuring
conditions. The pressing device measured resistance by using
compressed nitrogen in a pressure range of about 0.03 to bout 1.57
N/mm.sup.2 (0.1 bar to 5 bar).
[0167] The pressure acting on both the bipolar plate and an MEA of
a sample in a measurement stack placed in the pressing device was
1.4 N/mm.sup.2. Two gold-coated current collectors were placed
between a pair of presses of the pressing device, with spacing
blocks respectively disposed between the current collectors and the
presses.
[0168] Two sheets of carbon paper were placed between the current
collectors, respectively, and a sample whose resistance was to be
measured was placed between the two sheets of carbon paper. Then,
the resistance of the sample was measured while increasingly
applying a pressure to press the measurement stack including the
sample. In other words, a cross-section of the measurement stack
included, from its top, a press, a spacing block, a current
collector, a carbon paper, the sample, another carbon paper,
another current collector, another spacing block, and another
press.
[0169] The results of measuring the electric resistances of the
bipolar plates are shown in FIG. 2 and Table 1.
[0170] Referring to FIG. 2, the electric resistance characteristics
of the bipolar plates of Examples 1-1 to 1-3 were found to be
excellent.
TABLE-US-00001 TABLE 1 Applied pressure (N/mm.sup.2) Example 0.03
0.31 0.78 1.57 Example 1-1 1563 134.7 50.4 20.7 Example 1-2 338
30.84 16.79 11.84 Example 1-3 964 48.08 20.15 12.51
Example 2-1
Manufacture of Bipolar Plate by Using a Mixture of BPS-a and Timrex
in a Weight Ratio of 1:1 and Stainless Steel Plate Having Grooves
of about 5 .mu.m in Width and Depth
[0171] A bipolar plate for a fuel cell was manufactured in the same
manner as in Example 1-2, except that the mixed ratio of BPS-a of
Formula 14 and Timrex was varied to be 1:1 by weight.
Example 2-2
Manufacture of Bipolar Plate by Using a Mixture of BPS-a and Timrex
in a Weight Ratio of 1:2 and Stainless Steel Plate Having Grooves
of about 5 .mu.m in Width and Depth
[0172] A bipolar plate for a fuel cell was manufactured in the same
manner as in Example 2-1, except that the mixed ratio of BPS-a and
Timrex was varied to be 1:2 by weight. Here, Example 2-2 is the
same as Example 1-2.
Example 2-3
Manufacture of Bipolar Plate by Using a Mixture of BPS-a and Timrex
in a Weight Ratio of 1:4 and Stainless Steel Plate Having Grooves
of about 5 .mu.m in Width and Depth
[0173] A bipolar plate for a fuel cell was manufactured in the same
manner as in Example 2-1, except that the mixed ratio of BPS-a and
Timrex was varied to be 1:4 by weight.
Example 3-1
Manufacture of Bipolar Plate by Using a Mixture of BPS-a and Vulcan
Xc-72 in a Weight Ratio of 1:0.25 and Stainless Steel Plate Having
Grooves of about 5 .mu.m in Width and Depth
[0174] A bipolar plate for a fuel cell was manufactured in the same
manner as in Example 2-1, except that Vulcan XC-72 was used instead
of Timrex, and a mixed ratio of BPS-a and Vulcan XC-72 was 1:0.25
by weight.
Example 3-2
Manufacture of Bipolar Plate by Using a Mixture of BPS-a and Vulcan
XC-72 in a Weight Ratio of 1:0.5 and Stainless Steel Plate Having
Grooves of about 5 .mu.m in Width and Depth
[0175] A bipolar plate for a fuel cell was manufactured in the same
manner as in Example 3-1, except that the mixed ratio of BPS-a and
Vulcan XC-72 was varied to be 1:0.5 by weight.
Example 3-3
Manufacture of Bipolar Plate by Using a Mixture of BPS-a and Vulcan
XC-72 in a Weight Ratio of 1:1 and Stainless Steel Plate Having
Grooves of about 5 .mu.m in Width and Depth
[0176] A bipolar plate for a fuel cell was manufactured in the same
manner as in Example 3-1, except that the mixed ratio of BPS-a and
Vulcan XC-72 was varied to be 1:1 by weight.
Example 3-4
Manufacture of Bipolar Plate by Using a Mixture of BPS-a and Vulcan
XC-72 in a Weight Ratio of 1:2 and Stainless Steel Plate Having
Grooves of about 5 .mu.m in Width and Depth
[0177] A bipolar plate for a fuel cell was manufactured in the same
manner as in Example 3-1, except that the mixed ratio of BPS-a and
Vulcan XC-72 was varied to be 1:2 by weight.
Example 3-5
Manufacture of Bipolar Plate by Using a Mixture of BPS-a and Vulcan
XC-72 in a Weight Ratio of 1:4 and Stainless Steel Plate Having
Grooves of about 5 .mu.m in Width and Depth
[0178] A bipolar plate for a fuel cell was manufactured in the same
manner as in Example 3-1, except that the mixed ratio of BPS-a and
Vulcan XC-72 was varied to be 1:4 by weight.
Example 4-1
Manufacture of Bipolar Plate by Using a Mixture of BPS-a and Timrex
in a Weight Ratio of 1:0.5 and Stainless Steel Plate Having Grooves
of about 20 .mu.m in Width and Depth
[0179] 5.5 g of N,N-dimethylacetamide was added to 3.4 g of BPS-a
of Formula 14 as a solvent and then stirred. The mixture was heated
to 40-50.degree. C. to prepare a BPS-a solution.
[0180] 1.7 g of Timrex as conducting carbon was added to the BPS-a
solution and mixed for 1 hour to obtain a slurry for forming a
coating layer. Herein, BPS-a and Timrex were mixed in a weight
ratio of 1:0.5.
[0181] The coating layer forming slurry was coated on a stainless
steel plate having a thickness of 1.2 mm and grooves of about 20
.mu.m in width and depth to a thickness of about 50 .mu.m by using
tape casting.
[0182] The stainless steel plate coated with the coating layer
forming slurry was dried in a 100.degree. C.-oven for 4 hours to
remove the solvent.
[0183] Then, the resulting metal plate was thermally treated at
250.degree. C. to form a coating layer containing a polymer of
BPS-a and Timrex on the stainless steel plate, thereby completing
the manufacture of a bipolar plate for a fuel cell. The coating
layer had a thickness of about 5 .mu.m.
[0184] The stainless steel plate having the grooves of about 20
.mu.m in width and depth was prepared in the same manner as in
Example 1-3.
Example 4-2
Manufacture of Bipolar Plate by Using a Mixture of BPS-a and Timrex
in a Weight Ratio of 1:1 and Stainless Steel Plate Having Grooves
of about 20 .mu.m in Width and Depth
[0185] A bipolar plate for a fuel cell was manufactured in the same
manner as in Example 4-1, except that the mixed ratio of BPS-a and
Timrex was varied to be 1:1 by weight.
Example 4-3
Manufacture of Bipolar Plate by Using a Mixture of BPS-a and Timrex
in a Weight Ratio of 1:2 and Stainless Steel Plate Having Grooves
of about 20 .mu.m in Width and Depth
[0186] A bipolar plate for a fuel cell was manufactured in the same
manner as in Example 4-1, except that the mixed ratio of BPS-a and
Timrex was varied to be 1:2 by weight.
Example 4-4
Manufacture of Bipolar Plate by Using a Mixture of BPS-a and Timrex
in a Weight Ratio of 1:4 and Stainless Steel Plate Having Grooves
of about 20 .mu.m in Width and Depth
[0187] A bipolar plate for a fuel cell was manufactured in the same
manner as in Example 4-1, except that the mixed ratio of BPS-a and
Timrex was varied to be 1:4 by weight.
Comparative Example 1
Manufacture of Bipolar Plate by Using a Mixture of Phenol Resin and
Vulcan XC-72 in a Weight Ratio of 1:1
[0188] A bipolar plate for a fuel cell was manufactured in the same
manner as in Example 3-3, except that phenol resin was used instead
of BPS-a.
Comparative Example 2
Manufacture of Bipolar Plate by Using a Mixture of Phenol Resin and
Vulcan XC-72 in a Weight Ratio of 1:2
[0189] A bipolar plate for a fuel cell was manufactured in the same
manner as in Example 3-4, except that phenol resin was used instead
of BPS-a.
Comparative Example 3
Manufacture of Bipolar Plate by Using a Mixture of Phenol Resin and
Vulcan XC-72 in a Weight Ratio of 1:0.5
[0190] A bipolar plate for a fuel cell was manufactured in the same
manner as in Example 3-2, except that phenol resin was used instead
of BPS-a.
[0191] Resistance characteristics of the bipolar plates for a fuel
cell manufactured in Examples 2-1 through 2-3 at different applied
pressures were measured. The results are shown in FIG. 3 and Table
2.
TABLE-US-00002 TABLE 2 BPS-a:Timrex Applied pressure (N/mm.sup.2)
(weight ratio) 0.03 0.31 0.78 1.57 1:1 468 53.895 32.255 24.116 1:2
338 30.845 16.7925 11.84 1:4 297 26.135 15.155 11.21
[0192] Referring to Table 2 and FIG. 3, the resistances of the
bipolar plates tend to decrease at higher pressures. Carbon paper
basically has a porous structure. However, the porosity of the
carbon paper becomes less as a higher pressure is applied, so that
the carbon paper may have a larger surface area with adjacent
surfaces. As a result, the electric resistance of the bipolar plate
is decreased. A pressure acting on the bipolar plate and an MEA of
a sample in a measurement stack placed in the pressing device was
about 1.4 N/mm.sup.2.
[0193] In addition, when the mixed ratio of BPS-a to the conducting
material (i.e., Timrex) was in the range of 1:2 to 1:4, the
resistance characteristics of the bipolar plate were excellent
without a weakening of the binding force of the coating layer to
the surface of the metal plate.
[0194] Resistance characteristics of the bipolar plates for a fuel
cell manufactured according to Examples 3-1 through 3-5 were
measured at different applied pressures. The results are shown in
FIG. 4 and Table 3.
TABLE-US-00003 TABLE 3 BPS-a:Vulcan XC-72 Applied pressure
(N/mm.sup.2) (weight ratio) 0.03 0.31 0.78 1.57 1:0.25 476 80.5
49.95 31.81 1:0.5 228 27.82 11.61 6.34 1:1 363.5 26.275 11.175
6.185 1:2 294 28.49 14.51 9.59 1:4 387 37.02 19.04 12.67
[0195] Resistance characteristics of the bipolar plates for a fuel
cell manufactured according to Comparative Examples 1 through 3
were measured at different applied pressures. The results are shown
in FIG. 5 and Table 4.
TABLE-US-00004 TABLE 4 Phenol resin:Vulcan XC-72 Applied pressure
(N/mm.sup.2) (weight ratio) 0.03 0.31 0.78 1.57 1:0.5 626.5 53.355
37.58 30.59 1:1 520.5 35.4 17.575 11.12 1:2 674 43.95 27.25
20.65
[0196] Referring to FIG. 5 and Table 4, the bipolar plates of
Comparative Examples 1 through 3 had poorer resistance
characteristics as compared to those of Examples 3-3, 3-4 and 3-2,
respectively.
[0197] The resistance to acid of each of the bipolar plates of
Examples 2-1 and 2-2 and Comparative Examples 1 and 2 was
evaluated.
[0198] The resistance to acid was evaluated from the corrosion
characteristics of the surface of the metal plate coated with the
polymer of the benzoxazine-based compound and the conducting
material by using an electrochemical method. A potentiodynamic
method was used at a voltage of -0.15V to 1.3V at a scan rate of 5
mV/sec to measure the resistance to acid. An Ag/AgCl electrode was
used as a reference electrode.
[0199] The results of the test of resistance to acid are shown in
FIG. 6.
[0200] Referring to FIG. 6, the corrosion currents for the bipolar
plates of Examples 2-1 and 2-2 were found to be relatively lower
than those for the bipolar plates of Comparative Examples 1 and
2.
[0201] Resistance characteristics of the bipolar plates of Examples
4-1 to 4-4 for use in fuel cells were measured at different
pressures. The results are shown in FIG. 7 and Table 5.
TABLE-US-00005 TABLE 5 Applied pressure (N/mm.sup.2) BPS-a:Timrex
0.03 0.31 0.78 1.57 1:0.5 286 29.12 12.88 6.79 1:1 354 26.98 11.32
6.21 1:2 388 29.47 14.82 9.87 1:4 434 36.42 18.89 12.42
[0202] As described above, according to the one or more of the
above embodiments of the present invention, a bipolar plate for a
fuel cell that has excellent resistance to acid and electrical
conductivity in a wide range of temperatures may be manufactured at
lower costs by forming a coating layer containing a polymer of an
oxazine compound, particularly a benzoxazine-based compound that is
resistant to acid on a surface of a metal plate.
[0203] It should be understood that the exemplary embodiments
described therein should be considered in a descriptive sense only
and not for purposes of limitation. Descriptions of features or
aspects within each embodiment should typically be considered as
available for other similar features or aspects in other
embodiments.
* * * * *